The present invention relates generally to fluid infusion systems, and more particularly to an improved flow metering apparatus for such systems.
The infusion of fluids into the human body is usually accomplished by means of an administration set in conjunction with metering apparatus which controls the rate of flow of fluid through the set. Peristaltic-type pumps, which function by repetitively compressing and expanding a section of tubing, have proven particularly attractive for use in metering apparatus since they do not introduce the possibility of leakage or contamination into the system, while providing positive control of fluid flow through the system.
One form of peristaltic-type pump which is particularly well adapted for infusion applications is described in the co-pending application of Thurman S. Jess, Ser. No. 759,178, filed Jan. 13, 1977, now U.S. Pat. No. 4,155,362. Basically, this pump construction includes individually spring-biased rollers in the pump rotor which provide a uniform compression force, and a spring-biased plunger which restricts the lumen of the administration set downline of the pump rotor to provide a back pressure against which the pump must work. This prevents the release of dissolved gas in the tubing section, assists in restoring the tubing to its original shape following compression by the pump, and prevents uncontrolled gravity flow in the event of pump failure.
In many applications, such as where medication is being administered, it is necessary that the operation of the peristaltic pump be precisely controlled to infuse only a predetermined volume of fluid at a predetermined rate. Thus, the need has developed for a control system for peristaltic-type infusion pumps which enables the operator to preset a quantity and rate of infusion, and which continuously monitors the performance of the pump to insure compliance with the preset parameters by interrupting operation and alerting the operator in the event of a malfunction. Furthermore, it is desirable that the system be fail-safe, and substantially unaffected in operation or accuracy by power line interruptions or transients. The metering apparatus of the present invention provides these features in an integrated unit which is simple and convenient to use.
Accordingly, it is a general object of the present invention to provide a new and improved system for infusing fluids into the human body.
It is a more specific object of the present invention to provide a new and improved metering apparatus for use in conjunction with an administration set for infusing fluids into the human body.
It is another object of the present invention to provide a peristaltic-type pump and control system which provides for accurate administration of a predetermined quantity of fluid at a predetermined rate.
It is another object of the present invention to provide a fluid metering apparatus which provides improved metering accuracy and protection against malfunction.
It is another object of the invention to provide a self-contained fluid metering apparatus which is simple and convenient to use.